Mobile information terminal and placement area acquisition method

ABSTRACT

A mobile information terminal that can acquire an optimum placement area for a controllable object, regardless of variability in user&#39;s gripping features among individuals. A pressure sensor array acquires a gripping pressure distribution; a gripping pressure logger records time-series changes in gripping pressure at each pressure sensor forming the pressure sensor array; a gripping pressure change point detection unit includes a gripping pressure change amount calculation section that acquires time-series changes in gripping pressure at each pressure sensor and determines whether the change in gripping pressure per unit time exceeds a predetermined value at any pressure sensor; and a placement area acquisition section specifies, when the change in gripping pressure per unit time exceeds the predetermined value at any pressure sensor, an optimum placement area for a controllable object with reference to a position where the change in gripping pressure per unit time exceeds the predetermined value.

TECHNICAL FIELD

The present invention relates to a mobile information terminal having afunction to determine a user's operation state (one-handed or two-handedoperation, etc.) from gripping features obtained when the mobileinformation terminal is gripped and a placement area acquisition method.

BACKGROUND ART

Mobile information terminals having a touch sensitive screen as a userinterface have been coming into use in recent years. The user canintuitively operate the mobile information terminal with a touchsensitive screen by touching the screen with a finger or by sliding thefinger on the screen. Many recent mobile information terminalsincorporate an accelerometer, and those mobile information terminals canautomatically switch the display orientation of the display screen inaccordance of the direction of gravitational force sensed by theaccelerometer. This allows the user to use the mobile informationterminal in a variety of gripping states and operation states accordingto the circumstances. For example, the user may grip the mobileinformation terminal in the right hand and operate the terminal with theright fingers alone (right thumb mainly), may grip the mobileinformation terminal in the left hand and operate the terminal with theleft fingers alone (left thumb mainly), may grip the mobile informationterminal in the right hand and operate the terminal with the leftfingers alone (left index finger mainly), and may grip the mobileinformation terminal in the left hand and operate the terminal with theright fingers alone (right index finger mainly). Moreover, the user maynot grip the mobile information terminal but may place it on a stand andoperate it with right fingers or left fingers, and may also grip themobile information terminal in both hands and operate it with fingers ofboth hands (both thumbs mainly), for example.

Although the gripping states and operation states of the mobileinformation terminal vary as described above, conventional mobileinformation terminals cannot perform screen display suited to eachgripping state and each operation state. For example, if the user gripsthe terminal in the right (left) hand and attempts to operate the touchsensitive screen with the right (left) thumb (this operation method willbe referred to as one-handed operation), some areas of the touchsensitive screen, such as the top right corner, the bottom left corner,the top left corner, and the bottom right corner, become difficult toreach for the right (left) thumb. If an icon or link is displayed inthose areas, it has been difficult for the user to touch the icon orlink displayed in those areas while performing one-handed operation. Forexample, when the user of the mobile information terminal is going tooperate the mobile information terminal, while standing in a movingtrain, the user would hold on to a strap or a rail with one hand so thathe or she will not stagger and would perform one-handed operation of themobile information terminal with the other hand.

If an icon or link the user wants to reach is displayed in an area thatis difficult to reach for the right (left) thumb on the touch sensitivescreen, the user should give up the operation until the next time thetrain stops and operate the mobile information terminal with both handswhen the train has stopped, or should release the strap or railtemporarily in the moving train and operate the mobile informationterminal with both hands temporarily. If the train jolts while the useris not holding on to the strap or rail, the user may fall down. If thisoccurs in a crowded train, the user could bump into another passenger orcould step on the foot of another passenger. The same inconvenience willoccur when the user attempts to operate the mobile information terminalwith one hand while carrying in the other hand a load that cannot becarried on his or her back. The user has to lower the load onto theground and then operate the mobile information terminal.

A portable terminal in Patent Literature 1 utilizes a touch sensor (leftsensor) disposed in the upper part of the left edge of the housing and atouch sensor (right sensor) disposed in the upper part of the right edgeof the housing and solves the problems described above by determiningwhether the user's current holding state is left-handed operation,right-handed operation, or two-handed operation, using the states ofthumbs detected by the left and right sensors and the detected state ofthe touch sensitive screen. When the detected states of the left sensor,right sensor, and touch sensitive screen are expressed by a circle(detection) or a cross (no detection), if the left and right sensors andthe touch sensitive screen make no detection, for example, the state canbe expressed as (left sensor, right sensor, touch sensitive screen)=(x,x, x). When the initial state S1 is defined as a state in which the useris neither gripping the portable terminal nor touching the touchsensitive screen, the initial state Si can be expressed as (x, x, x).When a change from the initial state (x, x, x) to a state (O, x, x) isdetected, it is determined that the left thumb is placed on the upperpart of the left edge of the housing of the portable terminal, and thestate shifts to a left-hand-holding state S2. When a change from theleft-hand-holding state S2 (O, x, x) to the state (x, x, x) is detected,it is determined that the thumb is moving to touch the touch sensitivescreen, and the state shifts to a prior-to-left-handed-operation stateS3. When a change from the prior-to-left-handed-operation state S3 (x,x, x) to a state (x, x, O) is detected, it is determined that the thumbhas touched the touch sensitive screen, and the state shifts to asubsequent-to-left-handed-operation state S4. When a change from theleft-hand-holding state S2 (O, x, x) to a state (O, x, O) is detected,it is determined that the terminal is held in the left hand and thetouch sensitive screen is operated with a right finger, and the statechanges to a left-hand-holding right-handed-operation state S5.

The same goes for the right hand. When a change from the initial state(x, x, x) to a state (x, O, x) is detected, it is determined that theright thumb is placed on the upper part of the right edge of the housingof the portable terminal, and the state shifts to a right-hand-holdingstate S6. When a change from the right-hand-holding state S6 (x, O, x)to a state (x, x, x) is detected, it is determined that the thumb ismoving to touch the touch sensitive screen, and the state shifts to aprior-to-right-handed-operation state S7. When a change from theprior-to-right-handed-operation state S7 (x, x, x) to a state (x, x, O)is detected, it is determined that the thumb has touched the touchsensitive screen, and the state shifts to asubsequent-to-right-handed-operation state S8. When a change from theright-hand-holding state S6 (x, O, x) to a state (x, O, O) is detected,it is determined that the terminal is held in the right hand and thetouch sensitive screen is operated with a left finger, and the stateshifts to a right-hand-holding left-handed-operation state S9. Theterminal in Patent Literature 1 determines whether the user's currentholding state is left-handed operation, right-handed operation, ortwo-handed operation, as described above, and re-positions the controlbuttons on the touch sensitive screen so that they can be reached easilyin any holding state.

Patent literature 1: Japanese Patent Application Laid Open No.2009-169820

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The portable terminal in Patent Literature 1, however, has the followingproblems in managing the user's current holding state. A first problemis that the portable terminal in Patent Literature 1 does not considervariability in the user's gripping manner among individuals.Accordingly, the portable terminal in Patent Literature 1 does not seemto increase the accuracy of determining the user's holding state above acertain level. For example, in the left-hand-holdingright-handed-operation state S5, the user does not always place the leftthumb on the upper part of the left edge of the housing of the portableterminal. The user may hold the portable terminal without placing theleft thumb on the upper part of the left edge of the housing and maycontort the thumb in such a direction that the tip of the thumb facesthe user's face and may press the base of the thumb against the middlepart of the left edge of the housing. If the user holds the lower partof the portable terminal, the left sensor disposed in the upper part ofthe left edge of the housing may not detect anything. Then, the portableterminal in Patent Literature 1 cannot determine the user's holdingstate correctly and cannot re-position the control buttons appropriatelyfor each holding state.

A second problem is that a single detection state detected by thecombination of the left sensor, right sensor, and touch sensitive screenrepresents a plurality of user's holding states, depending on thetransition route. For example, the detected state (x, x, x) representsany holding state of the initial state S1,prior-to-left-handed-operation state S3, orprior-to-right-handed-operation state S7, depending on the transitionroute. For example, suppose that, although the portable terminal inPatent Literature 1 has determined that the detected state (x, x, x)represents the prior-to-left-handed-operation state S3, thedetermination is wrong, and the correct state is theprior-to-right-handed-operation state S7. Then, when the state shifts toa state (x, O, x), the portable terminal in Patent Literature 1 wouldmisjudge the holding state after the shift is thesubsequent-to-left-handed-operation state S4. In fact, since theprior-to-right-handed-operation state S7 has shifted to a state (x, x,O), the correct determination is that the state has shifted to thesubsequent-to-right-handed-operation state S8. From the misjudgedsubsequent-to-left-handed-operation state S4, further misjudgments willbe repeated in determining the subsequent states.

In the portable terminal in Patent Literature 1, if a single misjudgmentis made in the process of determining the user's holding state,subsequently determined states will be all wrong. Re-positioning controlbuttons on the touch sensitive screen in accordance with suchmisjudgment would be troublesome for the user and would result inincreased inconvenience to the user. Therefore, it is an object of thepresent invention to provide a mobile information terminal that canappropriately acquire an optimum placement area for a controllableobject, regardless of the variability in user's gripping featuresbetween individuals.

Means to Solve the Problems

A mobile information terminal of the present invention includes apressure sensor array, a gripping pressure logger, a gripping pressurechange point detection unit, and a placement area acquisition section.The gripping pressure change point detection unit includes a grippingpressure change amount calculation section. The gripping pressure loggerrecords time-series changes in gripping pressure at each pressure sensorforming the pressure sensor array. The gripping pressure change amountcalculation section acquires time-series changes in gripping pressure ateach pressure sensor and determines whether the amount of change ingripping pressure per unit time exceeds a predetermined value at anypressure sensor. If the amount of change in gripping pressure per unittime exceeds the predetermined value at any pressure sensor, theplacement area acquisition section acquires a placement area for acontrollable object with reference to a position where the amount ofchange in gripping pressure per unit time exceeds the predeterminedvalue.

Effects Of The Invention

The mobile information terminal according to the present invention canappropriately acquire an optimum placement area for a controllableobject, regardless of variability in user's gripping features amongindividuals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a view showing gripping features in two-handed operation withportrait display.

FIG. 1B is a view showing gripping features in one-handed operation withportrait display.

FIG. 2A is a view showing gripping features in two-handed operation withlandscape display.

FIG. 2B is a view showing gripping features in one-handed operation withlandscape display.

FIG. 3A is a view showing a state in which the controlling finger hasbeen moved upward in one-handed operation.

FIG. 3B is a view showing a state in which the controlling finger hasbeen moved downward in one-handed operation.

FIG. 3C is a view showing an area in which the gripping pressure changeswhen the controlling finger has been moved.

FIG. 4 is a view showing examples of pressure sensor arrays included inthe portable terminals according to all embodiments.

FIG. 5A to FIG. 5D are views illustrating the relationship between thepositions of gripping pressure change points and the operation state:Shown at FIG. 5A is left-handed operation with portrait display; shownat FIG. 5B is right-handed operation with portrait display; shown atFIG. 5C is left-handed operation with landscape display; and shown atFIG. 5D is right-handed operation with landscape display.

FIG. 6A to FIG. 6D are views illustrating the relationship among thepositions of gripping pressure change points, screen orientation, andthe operation state: Shown at FIG. 6A is left-handed operation withportrait display, with the top of the screen shown at the top edge andthe bottom of the screen shown at the bottom edge; shown at FIG. 6B isright-handed operation with portrait display, with the top of the screenshown at the top edge and the bottom of the screen shown at the bottomedge; shown at FIG. 6C is left-handed operation with landscape display,with the top of the screen shown at the right edge and the bottom of thescreen shown at the left edge; and shown at FIG. 6D is right-handedoperation with landscape display, with the top of the screen shown atthe right edge and the bottom of the screen shown at the left edge.

FIG. 7A is a view showing an example of a controlling-finger movementrange in left-handed operation when the screen orientation is unknown.

FIG. 7B is a view showing an example of a controlling-finger movementrange in right-handed operation when the screen orientation is unknown.

FIG. 7C is a view showing an optimum placement area obtained bysuperimposing the controlling-finger movement ranges shown in FIGS. 7Aand 7B.

FIG. 8A is a view showing an example of a controlling-finger movementrange in left-handed operation when the screen orientation is known.

FIG. 8B is a view showing an optimum placement area obtained from thecontrolling-finger movement range shown in FIG. 8A.

FIG. 9A is a view showing an example of an optimum placement area whenthe gripping pressure change point is in a comparatively lower part.

FIG. 9B is a view showing an example of an optimum placement area whenthe gripping pressure change point is in a comparatively higher part.

FIG. 10A to FIG. 10D are views showing examples of a log recorded by atouch-sensitive-screen logger: Shown at FIG. 10A is a log of left-handedoperation with portrait display; shown at FIG. 10B is a log ofright-handed operation with portrait display; shown at FIG. 10C is a logof left-handed operation with landscape display; shown at FIG. 10D is alog of right-handed operation with landscape display.

FIG. 11A to FIG. 11C are views showing examples of optimum positions ofcontrollable objects: Icons are shown at FIG. 11A; keys are shown atFIG. 11B; and links are shown at FIG. 11C.

FIG. 12 is a block diagram showing the configuration of a portableterminal according to a first embodiment.

FIG. 13 is a flowchart illustrating the operation of the portableterminal according to the first embodiment.

FIG. 14 is a block diagram showing the configuration of a portableterminal according to a second embodiment.

FIG. 15 is a flowchart illustrating the operation of the portableterminal according to the second embodiment.

FIG. 16 is a block diagram showing the configuration of a portableterminal according to a third embodiment.

FIG. 17 is a flowchart illustrating the operation of the portableterminal according to the third embodiment.

FIG. 18 is a block diagram showing the configuration of a portableterminal according to a fourth embodiment.

FIG. 19 is a flowchart illustrating the operation of the portableterminal according to the fourth embodiment.

FIG. 20 is a block diagram showing the configuration of a portableterminal according to a fifth embodiment.

FIG. 21 is a flowchart illustrating the operation of the portableterminal according to the fifth embodiment.

FIG. 22 is a block diagram showing the configuration of a portableterminal according to a sixth embodiment.

FIG. 23 is a flowchart illustrating the operation of the portableterminal according to the sixth embodiment.

FIG. 24 is a block diagram showing the configuration of a portableterminal according to a seventh embodiment.

FIG. 25 is a flowchart illustrating the operation of the portableterminal according to the seventh embodiment.

FIG. 26 is a block diagram showing the configuration of a portableterminal according to an eighth embodiment.

FIG. 27 is a flowchart illustrating the operation of the portableterminal according to the eighth embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

Now, embodiments of the present invention will be described in detail.Components having the same function are denoted by the same referencenumerals, and duplicate descriptions will be omitted.

Description of Terms

Mobile Information Terminal

Specific examples of mobile information terminals include portableterminals, PDAs, portable gaming devices, electronic organizers, andelectronic book readers. Besides the devices listed above, the mobileinformation terminal of the present invention can be any device that (1)is used in a gripped state and can acquire the gripping pressure whileit is being used, (2) can be operated with one hand and with both hands,and (3) has a touch sensitive screen. In the description of embodiments,a portable terminal will be described in detail as an example.

One-handed Operation, Two-handed Operation

Using the right thumb for touch sensitive screen operation whilegripping the mobile information terminal in the right hand and using theleft thumb for touch sensitive screen operation while gripping themobile information terminal in the left hand are both referred to asone-handed operation. Using left fingers for touch sensitive screenoperation while gripping the mobile information terminal in the righthand and using right fingers for touch sensitive screen operation whilegripping the mobile information terminal in the left hand are bothreferred to as two-handed operation.

Display Orientation, Screen Orientation

A display orientation is an orientation distinguished by whether thelonger side of the rectangular display screen of the mobile informationterminal is displayed as the vertical direction or the horizontaldirection. A screen orientation is the top-to-bottom direction of thedisplay screen of the mobile information terminal.

Portrait Display, Landscape Display

Displaying the longer side of the display screen of the mobileinformation terminal as the vertical direction is referred to asportrait display. Displaying the longer side of the display screen ofthe mobile information terminal as the horizontal direction is referredto as landscape display.

Controlling Finger

A finger that touches the touch sensitive screen of the mobileinformation terminal to control the mobile information terminal isreferred to as a controlling finger.

Change Point

When the amount of change in gripping pressure per unit time, calculatedfor each pressure sensor by a gripping pressure change amountcalculation section, which will be included in all the embodimentsdescribed later, exceeds a predetermined value, the position of thepressure sensor on the mobile information terminal will be referred toas a change point.

Change Frequency, Change Frequency Exceeding Point

A change frequency is the number of times counted by a change frequencycounting section, which will be included in second, fourth, sixth,seventh, and eighth embodiments described later, each pressure sensorbecomes a change point in a predetermined period of time. The positionon the mobile information terminal of the pressure sensor at which thechange frequency exceeds a predetermined frequency is referred to as achange frequency exceeding point.

Gripping Pressure Change Point

A gripping pressure change point is a general term for the change pointand the change frequency exceeding point.

Controllable Object

User-controllable objects that are displayed on the display screen ofthe mobile information terminal are generically referred to ascontrollable objects. Specifically, the controllable objects includeicons, links, keyboards, and the like.

[Difference in Gripping Features Between One-Handed Operation andTwo-Handed Operation]

The mobile information terminal of the present invention is not limitedto a portable terminal and can be a variety of devices, as describedabove. For ease of understanding, however, a portable terminal having atouch sensitive screen will be described as an example in allembodiments of the present invention. States of the user's left fingerswhen the user is gripping a portable terminal with a touch sensitivescreen will be described with reference to FIGS. 1A, 1B, 2A, 2B, 3A, 3B,and 3C. FIGS. 1A and 1B are views comparing gripping features betweenone-handed operation and two-handed operation, with portrait display. Aportable terminal 2 has a nearly rectangular shape, and a rectangulardisplay screen 2D is disposed on one face. The touch sensitive screen isformed on the display screen 2D but is not shown in the figures. FIGS.2A and 2B are views comparing gripping features between one-handedoperation and two-handed operation, with landscape display. FIGS. 3A,3B, and 3C are views illustrating a change in gripping pressure inone-handed operation. FIGS. 1A shows the state of the left hand whenportrait display, left-hand gripping, and right-handed operation areperformed. FIG. 1B shows the state of the left hand when portraitdisplay, left-hand gripping, and left-handed operation are performed.

Comparison between FIGS. 1A and 1B indicates that the gripping positionsof the left index finger IND, middle finger MID, ring finger ANN, andlittle finger LIT do not differ greatly, but the position of the thumbdiffers greatly. When portrait display, left-hand gripping, andright-handed operation are performed, as shown in FIG. 1A, the user'sleft thumb THM rests in a position outside the display screen 2D, sothat operation with a right finger will not be disturbed and the usercan see the display screen 2D easily. In contrast, when portraitdisplay, left-hand gripping, and left-handed operation are performed, asshown in FIG. 1B, the user's left thumb THM stands ready to touch auser-desired controllable object above the middle of the touch sensitivescreen 2D. The same goes for the landscape display (FIG. 2A shows thestate of the left hand when landscape display, left-hand gripping, andright-handed operation are performed, and FIG. 2B shows the state of theleft hand when landscape display, left-hand gripping, and left-handedoperation are performed).

Features that are not found in two-handed operation can be seen inone-handed operation. FIG. 3A is a view showing the limit of acounterclockwise movable range of the controlling finger (left thumbTHM) when portrait display, left-hand gripping, and left-handedoperation are performed. FIG. 3B is a view showing the limit of aclockwise movable range of the controlling finger (left thumb THM) whenportrait display, left-hand gripping, and left-handed operation areperformed. Both FIGS. 3A and 3B show ranges where the user can move theleft thumb easily as movable ranges. When the user can move thecontrolling finger (left thumb THM) as shown in FIGS. 3A and 3B, the tipof the controlling finger (left thumb THM) forms a circular locus aroundthe point of contact between the base of the thumb and the edge of theportable terminal 2, as shown in FIG. 3C. The gripping pressure in thevicinity of the point of contact between the base of the left thumb andthe edge of the portable terminal 2 (an elliptical area 2R enclosed by abroken line in FIG. 3C) varies from moment to moment while thecontrolling finger (left thumb THM) is contorting and touching thescreen.

On the other hand, as indicated by FIGS. 1A and 2A, in two-handedoperation, the gripping pressure does not change greatly in any areas ofthe portable terminal 2, including the elliptical area 2R enclosed by abroken line in FIG. 3C. Accordingly, if a change in gripping pressureexceeding a predetermined value occurs in any area on the edges of theportable terminal 2, it can be determined that the user is in theone-handed-operation state; and if a change in gripping pressureexceeding the predetermined value does not occur in any area on theedges of the portable terminal 2, it can be determined that the user isin the two-handed-operation state. If the number of times changes ingripping pressure occur (change frequency) is large in any area on theedges of the portable terminal 2 in a predetermined period of time, itmay be determined that the user is in the one-handed-operation state;and if the change frequency is small in any area of the edges of theportable terminal 2 in the predetermined period of time, it may bedetermined that the user is in the two-handed-operation state. Accordingto the present invention, on the basis of the above-described points, anoptimum placement area can be acquired for a controllable object, theoptimum placement area varying depending on whether the user is in theone-handed-operation state or the two-handed-operation state.

Pressure Sensor Array 11

A pressure sensor array 11 included in portable terminals 10, 20, 30,40, 50, 60, 70 and 80 in all embodiments of the present invention, shownin FIGS. 12, 14, 16, 18, 20, 22, 24, 26, will be described next withreference to FIG. 4. FIG. 4 is a view showing an example of the pressuresensor array 11 included in the portable terminals 10, 20, 30, 40, 50,60, 70 and 80 (represented by the portable terminal 2) in all theembodiments. FIG. 4 shows just an example and does not confine theposition of the pressure sensor array 11 used in the present invention.However, since the pressure sensor array 11 used in the presentinvention needs to measure changes in gripping pressure at the positionof contact between the base of the controlling finger (thumb) and anedge of the portable terminal 2 in one-handed operation, it is desirablethat individual sensors be disposed at regular intervals at all edges ofthe portable terminal 2. In the example shown in FIG. 4, for example,the pressure sensor array 11 included in the portable terminal 2includes a pressure sensor array U disposed on the upper edge of theportable terminal 2, a pressure sensor array L disposed on the left edgeof the portable terminal 2, a pressure sensor array R disposed on theright edge of the portable terminal 2, and a pressure sensor array Bdisposed on the bottom edge of the portable terminal 2. The pressuresensor array U includes four pressure sensors 11-U1, 11-U2, 11-U3, and11-U4. The pressure sensor array L includes seven pressure sensors11-L1, 11-L2, 11-L3, 11-L4, 11-L5, 11-L6, and 11-L7. The pressure sensorarray R includes seven pressure sensors 11-R1, 11-R2, 11-R3, 11-R4,11-R5, 11-R6, and 11-R7. The pressure sensor array B includes fourpressure sensors 11-B1, 11-B2, 11-B3, and 11-B4. Since the portableterminal 2 includes the pressure sensor array 11 in this manner, whenthe gripping pressure changes greatly in the elliptical area 2R enclosedby a broken line in FIG. 3C, described earlier, changes in grippingpressure can be observed by the pressure sensors 11-L5, 11-L6, and thelike. In one-handed operation with right-hand gripping and right-handedoperation, for example, changes in gripping pressure are observed by thepressure sensors 11-R5, 11-R6, and the like.

Operation of Gripping Pressure Logger 12

A gripping pressure logger 12 included in the portable terminals 10, 20,30, 40, 50, 60, 70 and 80 (represented by the portable terminal 2) inall the embodiments of the present invention, shown in FIGS. 12, 14, 16,18, 20, 22, 24, and 26, will be described next. The gripping pressurelogger 12 records values observed by all the pressure sensors (11-U1 to11-U4, 11-L1 to 11-L7, 11-R1 to 11-R7, and 11-B 1 to 11-B4) included inthe pressure sensor array 11 as time-series data at each pressure sensorfor use in determining the operation state, which will be describedlater.

Operation of Gripping Pressure Change Amount Calculation Section 13 a

A gripping pressure change amount calculation section 13 a included inthe portable terminals 10, 20, 30, 40, 50, 60, 70 and 80 (represented bythe portable terminal 2) in all the embodiments of the presentinvention, shown in FIGS. 12, 14, 16, 18, 20, 22, 24, and 26, will bedescribed next. One of the easiest ways of distinguishing betweenone-handed operation and two-handed operation from the time-series dataof gripping pressure at each pressure sensor, recorded by the grippingpressure logger 12, described above, is to determine whether an abruptchange in gripping pressure occurs at any pressure sensor. The grippingpressure change amount calculation section 13 a is a component fordetecting an abrupt change in gripping pressure. More specifically, thegripping pressure change amount calculation section 13 a acquirestime-series changes in gripping pressure at each sensor from thegripping pressure logger 12 and determines whether the amount of changein gripping pressure per unit time at each pressure sensor exceeds apredetermined value. The first derivative of the time-series data ofgripping pressure can be used as the amount of change in grippingpressure per unit time.

Operation of Change Frequency Counting Section 23 b

A change frequency counting section 23 b included in the portableterminals 20, 40, 60, and 80 (represented by the portable terminal 2) insecond, fourth, sixth, and eighth embodiments of the present invention,shown in FIGS. 14, 18, 22, and 26, will be described next. One method ofdistinguishing between one-handed operation and two-handed operationfrom the time-series data of gripping pressure recorded by the grippingpressure logger 12 at each pressure sensor can be based on the number ofabrupt changes in gripping pressure observed at the pressure sensor in apredetermined period of time. The change frequency counting section 23 bis a component for counting the number of abrupt changes in grippingpressure in the predetermined period of time. More specifically, thechange frequency counting section 23 b counts the number of times theamount of change in gripping pressure per unit time exceeds apredetermined value in each predetermined period of time.

Determination Operation of Placement Area Acquisition Section 51 or 61

The operation principle of a placement area acquisition section 51 or 61included in the portable terminals 10, 20, 50, and 60 (represented bythe portable terminal 2) in first, second, fifth, and sixth embodiments,shown in FIGS. 12, 14, 20, and 22, will be described next with referenceto FIGS. 5A to 5D. FIGS. 5A to 5D are views illustrating therelationship between the position of a gripping pressure change point 2Gand the operation state. Black rectangles in FIGS. 5A and 5B representpressure sensors that can observe a change in gripping pressure inone-handed operation when the display orientation of the display screen2D is portrait display. Black rectangles in FIGS. 5C and 5D representpressure sensors that can observe a change in gripping pressure inone-handed operation when the display orientation is landscape display.For example, the black rectangles in FIG. 5A represent the seven leftpressure sensors (11-L1 to 11-L7), and the black rectangles in FIG. 5Brepresent the seven right pressure sensors (11-R1 to 11-R7). At firstsight, among the pressure sensors represented by the black rectangles,the pressure sensors 11-L1 and 11-L2, for example, seem to be so highthat the base of the controlling finger, that is, the thumb THM, willnot touch them. However, when the user is using the portable terminal 2with the screen orientation upside down (with the top of the screendisplayed at the bottom of the figure) and when right-hand gripping andright-handed operation are performed, the pressure sensors 11-L1, 11-L2,and the like can touch the base of the controlling finger, that is, theright thumb THM. In the same way, when the user is using the portableterminal 2 with the screen orientation upside down (with the top of thescreen displayed at the bottom of the figure) and when left-handgripping and left-handed operation are performed, the pressure sensors11-R1, 11-R2, and the like can touch the base of the controlling finger,that is, the left thumb THM. The same goes for landscape display shownin FIGS. 5C and 5D.

As described above, when the user is performing one-handed operation, achange in gripping pressure is always observed by some of the pressuresensors on the top, bottom, right, and left edges of the portableterminal 2. In contrast, when the user is performing two-handedoperation, no change in gripping pressure is observed by any of thepressure sensors on the top, bottom, right, and left edges of theportable terminal 2. The placement area acquisition section 51 or 61included in the portable terminals 10, 20, 50, and 60 (FIGS. 12, 14, 20,and 22) in the first, second, fifth, and sixth embodiments determineswhether an amount of change in gripping pressure per unit time exceedsthe predetermined value at any of the pressure sensors on the top,bottom, right, and left edges, that is, whether a gripping pressurechange point exists. The placement area acquisition section 51 or 61specifies an optimum placement area according to the position of thegripping pressure change point when the amount of change exceeds thepredetermined value (or for a period of time for which the changefrequency exceeds the predetermined value). The placement areaacquisition section 51 or 61 determines that the operation state istwo-handed operation and does not execute the subsequent processes whenthere is no gripping pressure change point at any of the pressuresensors on the top, bottom, right, and left edges.

Determination Operation of Placement Area Acquisition Section 71 or 81

The determination operation of a placement area acquisition section 71or 81 included in the portable terminals 30, 40, 70, and 80 (representedby the portable terminal 2) in third, fourth, seventh, and eighthembodiments, shown in FIGS. 16, 18, 24, and 26, will be described nextwith reference to FIGS. 6A to 6D. FIGS. 6A to 6D are views illustratingthe relationship among the position of a gripping pressure change point,the screen orientation, and the operation state. Black rectangles inFIGS. 6A represent pressure sensors that can observe a change ingripping pressure in a state of left-hand gripping and left-handedoperation when the display orientation of the display screen 2D isportrait display with the top of the screen displayed at the top of thefigure. Black rectangles in FIGS. 6B represent pressure sensors that canobserve a change in gripping pressure in a state of right-hand grippingand right-handed operation when the display orientation is portraitdisplay with the top of the screen displayed at the top of the figure.Black rectangles in FIGS. 6C represent pressure sensors that can observea change in gripping pressure in a state of left-hand gripping andleft-handed operation when the display orientation is landscape displaywith the top of the screen displayed to the right of the figure. Blackrectangles in FIGS. 6D represent pressure sensors that can observe achange in gripping pressure in a state of right-hand gripping andright-handed operation when the display orientation is landscape displaywith the top of the screen displayed to the right of the figure. Asdescribed earlier, when the user is performing two-handed operation,none of the pressure sensors on the top, bottom, right, and left edgesof the portable terminal 2 observe a change in gripping pressure.

When the screen orientation (top-to-bottom direction) is known and whenan edge that includes the position of the pressure sensor that hasobserved a change in gripping pressure (gripping pressure change point)is identified, as described above, the placement area acquisitionsection 71 or 81 in the portable terminal 30, 40, 70, or 80 (FIG. 16,18, 24, or 26) determines whether the user's operation state isone-handed or two-handed operation, in accordance with the twoinformation items (the top-to-bottom direction and the position of thegripping pressure change point), and can further determine an optimumplacement area according to the position of the gripping pressure changepoint and also according to, in one-handed operation, whether it isleft-hand gripping and left-handed operation or right-hand gripping andright-handed operation. More specifically, when the gripping pressurechange point is on the right edge of the portable terminal 30, 40, 70,or 80 with reference to the screen orientation (top-to-bottomdirection), the placement area acquisition section 71 or 81 included inthe portable terminal 30, 40, 70, or 80 determines that the operationstate is right-hand gripping and right-handed operation and specifies anoptimum placement area according to the position of the grippingpressure change point. When the gripping pressure change point is on theleft edge of the portable terminal 30, 40, 70, or 80 with reference tothe screen orientation (top-to-bottom direction), the placement areaacquisition section 71 or 81 determines that the operation state isleft-hand gripping and left-handed operation and specifies an optimumplacement area according to the position of the gripping pressure changepoint. When the gripping pressure change point is not found on any edgeof the portable terminal 30, 40, 70, or 80, the operation state isdetermined to be two-handed operation, and the subsequent processes arenot executed.

Operation of Specifying Optimum Placement Area in Placement AreaAcquisition Section 51

The operation of specifying an optimum placement area in the placementarea acquisition section 51 included in the portable terminal 10 or 20(represented by the portable terminal 2) in the first or secondembodiment, shown in FIG. 12 or 14, will be described next withreference to FIGS. 7A, 7B, and 7C. FIGS. 7A, 7B, and 7C are viewsshowing examples of the placement area determined from a grippingpressure change point when the screen orientation (top-to-bottomdirection) is not known. FIG. 7A is a view showing an example ofcontrollable range 2F for the controlling finger (left thumb THM) inleft-hand gripping and left-handed operation. The controllable range 2Fcan be obtained by using the gripping pressure change point 2G as areference point. For example, the controllable range 2F can be set as afan-shaped area having a given width that is predetermined such that thecontrolling finger can easily touch the screen, within thecounterclockwise and clockwise movable angle ranges of the controllingfinger around the gripping pressure change point 2G. The movable angleof the thumb THM is roughly 90°, with some variability betweenindividuals. The radial width of the fan-shaped area should be set to anappropriate width such that an area that can be touched by small-handedpeople and an area that can be touched by large-handed people overlap,with variability in finger length among individuals taken intoconsideration.

FIG. 7B shows an example in which the gripping pressure change point 2Gappears at the same position as shown in FIG. 7A, the user uses theterminal upside down (with the top of the screen shown at the bottom ofthe figure), and right-hand gripping and right-handed operation areperformed. Although the gripping pressure change point 2G appears at thesame position as shown in FIG. 7A, a controllable range 2F that can beobtained by using the gripping pressure change point 2G as a referencepoint differs from that shown in FIG. 7A. Whether the relationshipbetween the gripping pressure change point 2G and the controllable range2F obtained therefrom becomes the positional relationship shown in FIG.7A or the positional relationship shown in FIG. 7B depends on the knownscreen orientation (top-to-bottom direction). If the function todetermine the top-to-bottom direction is not provided, as in theportable terminal 50 or 60, however, the range represented by polka dotsshown in FIG. 7C, including the standard controllable range 2Fdetermined as shown in FIG. 7A and the standard controllable range 2Fdetermined as shown in FIG. 7B, is set as a placement area 2FA. Therelative position of the gripping pressure change point with respect tothe standard placement area is fixed. The placement area is stored in aplacement area storage 52, together with the relative positioninformation thereof with respect to the gripping pressure change pointbefore the portable terminal is shipped. The relative positioninformation may be the coordinates of the center of gravity of theplacement area and the coordinates of the gripping pressure change pointor may also be the distance and angle between these two sets ofcoordinates on the coordinate system. If the position of the grippingpressure change point is acquired before the portable terminal has everbeen used, even though the screen orientation (top-to-bottom direction)of the display screen 2D is not known, an optimum placement area can beset by moving the placement area stored in the placement area storage 52with respect to the acquired gripping pressure change point inaccordance with the relative position information. The portableterminals 10 and 20 in the first and second embodiments do not have ascreen orientation acquisition section 31 and do not acquire the screenorientation (top-to-bottom direction) beforehand, which will bedescribed later in detail. Accordingly, the placement area acquisitionsection 51 of the portable terminals 10 and 20 in the first and secondembodiments specifies an optimum placement area by moving the placementarea 2FA, represented by polka dots in FIG. 7C, in accordance with thegripping pressure change point 2G.

Operation of specifying optimum placement area in placement areaacquisition section 71 The operation of specifying an optimum placementarea in the placement area acquisition section 71 included in theportable terminals 30 and 40 in the third and fourth embodiments shownin FIG. 16 and FIG. 18 will be described next with reference to FIGS.8A, 8B, 9A, and 9B. FIGS. 8A and 8B are views showing an example of aplacement area determined from a gripping pressure change point when thescreen orientation (top-to-bottom direction) is known. FIGS. 9A and 9Bare views showing an example of a change in the placement area,depending on the gripping pressure change point. FIG. 8A is a viewshowing an example of the controllable range 2F of the controllingfinger (left thumb THM) in left-hand gripping and left-handed operation.The controllable range 2F can be obtained with reference to the grippingpressure change point 2G, as described above. The controllable range 2Fcan be set as a fan-shaped area having a predetermined width such thatthe controlling finger can easily touch the screen, within thecounterclockwise and clockwise movable angles of the controlling fingeraround the gripping pressure change point 2G.

Since the screen orientation (top-to-bottom direction) is known forFIGS. 8A and 8B, the controllable range 2F obtained in FIG. 8A isdirectly set as the placement area 2FA beforehand, like the arearepresented by polka dots in FIG. 8B, and is stored in the placementarea storage 52 together with the relative position information thereofwith respect to the gripping pressure change point 2G. The portableterminals 30 and 40 in the third and fourth embodiments include thescreen orientation acquisition section 31, and the screen orientationacquisition section 31 can acquire the screen orientation (top-to-bottomdirection), which will be described later in detail. Accordingly, theplacement area acquisition section 71 of the portable terminals 30 and40 in the third and fourth embodiments specifies the optimum placementarea 2FA, represented by polka dots, in accordance with the screenorientation (top-to-bottom direction) and the gripping pressure changepoint 2G. Of course, since the relative positional relationship betweenthe position of the gripping pressure change point 2G and thecontrollable range 2F (placement area 2FA) is fixed, as shown in FIGS.9A and 9B, a vertical movement of the gripping pressure change point 2Gmoves the controllable range 2F (placement area 2FA) vertically. Thisgoes for FIGS. 7A, 7B, and 7C, as described earlier, and a verticalmovement of the griping pressure change point 2G moves the placementarea 2FA shown in FIG. 7C vertically.

Operation Principle of Placement Area Acquisition Section 81

The operation principle of the placement area acquisition section 81included in the portable terminals 70 and 80 in the seventh and eighthembodiments shown in FIG. 24 and FIG. 26 will be described next withreference to FIGS. 10A to 10D. FIGS. 10A to 10D are views showingexamples of a touch sensitive screen operation log recorded by atouch-sensitive-screen logger 82 included in the portable terminals 70and 80 in the seventh and eighth embodiments. The touch-sensitive-screenlogger 82 included in the portable terminal 80 in the eighth embodimentrecords a touch sensitive screen operation log for each combination ofthe operation state and the screen orientation in a time zone duringwhich the combination of the operation state and the screen orientationremains unchanged. For example, FIG. 10A shows an example of a touchsensitive screen operation log recorded by the touch-sensitive-screenlogger 82 in a time zone during which the conditions of left-handgripping, left-handed operation, and top of the screen being displayedat the top of the figure are satisfied, when the screen orientationacquisition section 31 acquires the screen orientation (top of thescreen displayed at the top of the figure) and when the operation stateis left-hand gripping and left-handed operation. FIG. 10B shows anexample of a touch sensitive screen operation log recorded by thetouch-sensitive-screen logger 82 in a time zone during which theconditions of right-hand gripping, right-handed operation, and the topof the screen being displayed at the top of the figure are satisfied,when the screen orientation acquisition section 31 acquires the screenorientation (top of the screen displayed at the top of the figure) andwhen the operation state is right-hand gripping and right-handedoperation. FIG. 10C shows an example of a touch sensitive screenoperation log recorded by the touch-sensitive-screen logger 82 in a timezone during which the conditions of left-hand gripping, left-handedoperation, and the top of the screen being displayed to the right of thefigure are satisfied, when the screen orientation acquisition section 31acquires the screen orientation (top of the screen displayed to theright of the figure) and when the operation state is left-hand grippingand left-handed operation. FIG. 10D shows an example of a touchsensitive screen operation log recorded by the touch-sensitive-screenlogger 82 in a time zone during which the conditions of right-handgripping, right-handed operation, and the top of the screen beingdisplayed to the right of the figure are satisfied, when the screenorientation acquisition section 31 acquires the screen orientation (topof the screen displayed to the right of the figure) and when theoperation state is right-hand gripping and right-handed operation.

In the figures, the touch sensitive screen operation log is representedby broken crosses. The size of the thumb is considered; a circular area(enclosed by a broken line in the figures) with a predetermined radiusaround a cross, which is a part of the touch sensitive screen operationlog, is considered as an area included in the placement area; and arange containing all of the circular areas can be acquired as an optimumplacement area 2FA. Since the placement area acquisition section 81 inthe portable terminals 70 and 80 of the seventh and eighth embodimentsacquires the optimum placement area 2FA on the basis of the touchsensitive screen operation log recorded by the touch-sensitive-screenlogger 82, the user's individual features can be considered, and userconvenience can be improved further.

Operation Principle of Placement Area Acquisition Section 61

The operation principle of the placement area acquisition section 61included in the portable terminals 50 and 60 in the fifth and sixthembodiments shown in FIG. 20 and FIG. 22 will be described next. Atouch-sensitive-screen logger 82 included in the portable terminals 50and 60 in the fifth and sixth embodiments records a touch sensitivescreen operation log for each operation state in a time zone duringwhich the operation state remains unchanged, the operation log beingclassified according to the position where the gripping pressure changepoint appears. More specifically, the touch-sensitive-screen logger 82classifies the operation log to cases (a) when the gripping pressurechange point appears at any of the edges of the portable terminals 50and 60 and (b) when the gripping pressure change point does not appearat any of the edges of the portable terminals 50 and 60; and records anoperation log for each gripping pressure change point separately onlyfor (a). The portable terminals 50 and 60 in the fifth and sixthembodiments do not have a screen orientation acquisition section 31 anddo not acquire the screen orientation (top-to-bottom direction)beforehand, which will be described later in detail. Therefore, asdescribed with reference to FIGS. 5A to 5D and FIGS. 7A to 7C, since thetop-to-bottom direction is unknown, even if it can be determined whetherthe operation state is one-handed operation or two-handed operation, itcannot be determined whether left-handed operation or right-handedoperation is performed in one-handed operation. In that case, in thesame way as described before with reference to FIG. 7C, an optimumplacement area is acquired to include both a controllable rangedetermined from an operation log at a gripping pressure change pointacquired in left-handed operation and a controllable range determinedfrom an operation log at the same gripping pressure change pointacquired in right-handed operation. As described above, since theplacement area acquisition section 61 included in the portable terminals50 and 60 in the fifth and sixth embodiments approximately acquires anoptimum placement area according to the touch-sensitive-screen operationlog recorded by the touch-sensitive-screen logger 82 even if the screenorientation (top-to-bottom direction) is unknown, variability amongindividual users can be taken into account, further increasing userconvenience.

Operation of Object Placement Correcting Section 53

The operation of an object placement correcting section 53 included inthe portable terminals 10, 20, 30, 40, 50, 60, 70, and 80 (representedby the portable terminal 2) in all the embodiments shown in FIGS. 12,14, 16, 18, 20, 22, 24, and 26 will be described next with reference toFIGS. 11A, 11B, and 11C. The object placement correcting section 53corrects the placement of a controllable object in accordance with theoptimum placement area specified by the placement area acquisitionsection 51, 61, 71, or 81. The controllable object is a general term forobjects that are displayed on the display screen 2D of the portableterminal 2 and can be controlled by the user, as described earlier. Morespecifically, they are icons, links, keyboards, and the like. When areasenclosed by a broken line in FIGS. 11A, 11B, and 11C are the optimumplacement area 2FA, user convenience is improved by moving icons thatcan be clicked on the display screen 2D of the portable terminal 2 intothe optimum placement area 2FA, as shown in FIG. 11A, for example.Re-positioning the displayed keys into the optimum placement area 2FA onthe display screen 2D as shown in FIG. 11B, for example, will be helpfulfor the user in preparing documents and searching for keywords.Re-positioning links on a page displayed by a web browser into theoptimum placement area 2FA as shown in FIG. 11C, for example, allows theuser to continue web browsing with less stress.

FIRST EMBODIMENT

The portable terminal 10 according to the first embodiment will bedescribed in detail with reference to FIGS. 12 and 13. FIG. 12 is ablock diagram showing the configuration of the portable terminal 10 inthis embodiment. FIG. 13 is a flowchart illustrating the operation ofthe portable terminal 10 in this embodiment. The portable terminal 10 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 13,the placement area acquisition section 51, the placement area storage52, and the object placement correcting section 53. The grippingpressure change point detection unit 13 includes the gripping pressurechange amount calculation section 13 a. The gripping pressure logger 12records time-series changes in gripping pressure at each pressure sensorforming the pressure sensor array 11 (S 12). The gripping pressurechange amount calculation section 13 a acquires the time-series changesin gripping pressure at each pressure sensor and determines whether theamount of change in gripping pressure per unit time at any pressuresensor exceeds the predetermined value (SS13 a).

The placement area storage 52 stores in advance the shape of a placementarea and relative position information of a gripping pressure changepoint with respect to the placement area. For example, the shape of aplacement area can be that described in “Operation of specifying optimumplacement area in placement area acquisition section 51”. When theamount of change in gripping pressure per unit time exceeds thepredetermined value at any of the pressure sensors, the placement areaacquisition section 51 specifies an optimum placement area for acontrollable object by shifting the placement area according to thegripping pressure change point detected by the gripping pressure changepoint detection unit 13 as a position (change point) where the amount ofchange in gripping pressure per unit time exceeds the predeterminedvalue, and the relative position information between the grippingpressure change point and the placement area, stored in the placementarea storage 52 (S51).

In contrast, when the amount of change in gripping pressure per unittime does not exceed the predetermined value at any of the pressuresensors, the placement area acquisition section 51 determines that theoperation state is two-handed operation and does not execute thesubsequent processes (S51). The object placement correcting section 53corrects the placement of the controllable object in accordance with theplacement area acquired by the placement area acquisition section 51(S53). As described before, when the placement area acquisition section51 determines that the operation state is two-handed operation and doesnot execute the subsequent processes (does not acquire a placementarea), the object placement correcting section 53 may re-position thecontrollable object at a position suited to two-handed operation(default position).

As described above, according to the portable terminal 10 of the firstembodiment, an optimum placement area for a controllable object can beappropriately acquired, regardless of variability in gripping featuresamong individual users.

SECOND EMBODIMENT

The portable terminal 20 according to the second embodiment, which hasfurther improved accuracy in acquiring an optimum placement areacompared with the portable terminal 10 of the first embodiment, will bedescribed next in detail with reference to FIGS. 14 and 15. FIG. 14 is ablock diagram showing the configuration of the portable terminal 20 ofthis embodiment. FIG. 15 is a flowchart illustrating the operation ofthe portable terminal 20 of this embodiment. The portable terminal 20 ofthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 23,the placement area acquisition section 51, the placement area storage52, and the object placement correcting section 53. The grippingpressure change point detection unit 23 includes the gripping pressurechange amount calculation section 13 a and the change frequency countingsection 23 b. This embodiment differs from the first embodiment in thatthe gripping pressure change point detection unit 13 in the firstembodiment is replaced by the gripping pressure change point detectionunit 23 in this embodiment, and the change frequency counting section 23b is added in the gripping pressure change point detection unit 23.

The gripping pressure logger 12 records time-series changes in grippingpressure at each pressure sensor forming the pressure sensor array 11(S12). The gripping pressure change amount calculation section 13 aacquires the time-series changes in gripping pressure at each pressuresensor and determines whether the amount of change in gripping pressureper unit time at any pressure sensor exceeds the predetermined value(SS13 a). The change frequency counting section 23 b counts the numberof times the amount of change in gripping pressure per unit time exceedsthe predetermined value (change frequency) in each predetermined periodof time (SS23 b). When the placement area acquisition section 51 isgiven in a period of time in which the counted change frequency exceedsa predetermined value for any of the pressure sensors, by the grippingpressure change point detection unit 23, a position where the countedchange frequency exceeds the predetermined value (change frequencyexceeding point) as a gripping pressure change point, the placement areaacquisition section 51 specifies an optimum placement area for acontrollable object by shifting the placement area read from theplacement area storage 52 with respect to the gripping pressure changepoint according to relative position information of the grippingpressure change point with the placement area (S51). In contrast, whenthere is no period of time in which the counted change frequency exceedsthe predetermined value for any of the pressure sensors, the placementarea acquisition section 51 determines that the operation state istwo-handed operation and does not execute the subsequent processes(S51). The object placement correcting section 53 corrects the placementof the controllable object in accordance with the placement areaspecified by the placement area acquisition section 51 (S53). Asdescribed before, when the placement area acquisition section 51determines that the operation state is two-handed operation and does notexecute the subsequent processes (does not specify a placement area),the object placement correcting section 53 may re-position thecontrollable object at a position suited to two-handed operation(default position).

As described above, the portable terminal 20 of the present embodimentcan not only provide the same advantages as in the first embodiment butalso acquire a placement area with higher accuracy. For example, when animpact is exerted in a part where the controlling finger is not placedand when a value indicated by a pressure sensor in the vicinity of theimpact changes abruptly, the portable terminal 10 in the firstembodiment could misjudge it as an operation of the controlling fingerand acquire a placement area with reference to that part. In theportable terminal 20 in this embodiment, however, an abrupt change invalue indicated by the pressure sensors is just counted as a singlechange, and an optimum placement area is specified with reference to thegripping pressure change point only after the change frequency at anypressure sensor exceeds the predetermined frequency. The number ofmisjudgments like that described above can be reduced considerably. Theportable terminal 20 in the second embodiment can acquire a placementarea with higher accuracy than the portable terminal 10 in the firstembodiment.

THIRD EMBODIMENT

The portable terminal 30 according to the third embodiment, which has anenhanced function of acquiring a placement area in comparison with theone in the portable terminal 10 of the first embodiment, will bedescribed next in detail with reference to FIGS. 16 and 17. FIG. 16 is ablock diagram showing the configuration of the portable terminal 30 inthis embodiment. FIG. 17 is a flowchart illustrating the operation ofthe portable terminal 30 in this embodiment. The portable terminal 30 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 13,the screen orientation acquisition section 31, the placement areaacquisition section 71, the placement area storage 52, and the objectplacement correcting section 53. The gripping pressure change pointdetection unit 13 includes the gripping pressure change amountcalculation section 13 a. This embodiment differs from the firstembodiment in that the screen orientation acquisition section 31, whichis not included in the first embodiment, is included in this embodiment,and the placement area acquisition section 51 in the first embodiment isreplaced with the placement area acquisition section 71 in thisembodiment.

The gripping pressure logger 12 records time-series changes in grippingpressure at each pressure sensor forming the pressure sensor array 11(S12). The gripping pressure change amount calculation section 13 aacquires the time-series changes in gripping pressure at each pressuresensor and determines whether the amount of change in gripping pressureper unit time at any pressure sensor exceeds the predetermined value(SS13 a). The screen orientation acquisition section 31 acquires thescreen orientation (top-to-bottom direction) of the portable terminal 30(S31). The placement area acquisition section 71 specifies an optimumplacement area for a controllable object in accordance with the acquiredscreen orientation (top-to-bottom direction) and a change point (S71).The operation of the placement area acquisition section 71 has beendescribed in detail in “Operation of specifying optimum placement areain placement area acquisition section 71”. In contrast, when no changepoint exists at any of the pressure sensors, the placement areaacquisition section 71 determines that the operation state is two-handedoperation and does not execute the subsequent processes (S71). Theobject placement correcting section 53 corrects the placement of thecontrollable object in accordance with the placement area specified bythe placement area acquisition section 71 (S53). In the same way as theplacement area acquisition section 51, described before, when theplacement area acquisition section 71 determines that the operationstate is two-handed operation and does not execute the subsequentprocesses (does not acquire a placement area), the object placementcorrecting section 53 may re-position the controllable object at aposition suited to two-handed operation (default position).

When the screen orientation is detected in step S31 and one longer sideof the screen is found to be the top, landscape display is used. Sincethe finger controllable range in one-handed operation is narrow, asshown in FIG. 2B, it is natural to grip the portable terminal in onehand and operate it with the other hand, or to grip it in two hands andoperate it with two hands.

Therefore, the placement of the objects is not corrected.

In the portable terminal 30 of this embodiment, the screen orientationacquisition section 31 acquires the screen orientation (top-to-bottomdirection), and the placement area acquisition section 71 acquires anoptimum placement area according to whether the user's operation stateis left-hand gripping and left-handed operation, right-hand gripping andright-handed operation, or two-handed operation, by using two pieces ofinformation (top-to-bottom direction and position of change point).Accordingly, besides the advantages of the first embodiment, afurther-limited optimum placement area can be acquired.

FOURTH EMBODIMENT

The portable terminal 40 according to the fourth embodiment, which hasan enhanced function of acquiring a placement area in comparison withthe one in the portable terminal 20 in the second embodiment, will bedescribed next in detail with reference to FIGS. 18 and 19. FIG. 18 is ablock diagram showing the configuration of the portable terminal 40 inthis embodiment. FIG. 19 is a flowchart illustrating the operation ofthe portable terminal 40 in this embodiment. The portable terminal 40 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 23,the screen orientation acquisition section 31, the placement areaacquisition section 71, the placement area storage 52, and the objectplacement correcting section 53. The gripping pressure change pointdetection unit 23 includes the gripping pressure change amountcalculation section 13 a and the change frequency counting section 23 b.This embodiment differs from the second embodiment in that the screenorientation acquisition section 31, which is not included in the secondembodiment, is included in this embodiment, and the placement areaacquisition section 51 in the second embodiment is replaced with theplacement area acquisition section 71 in this embodiment.

The gripping pressure logger 12 records time-series changes in grippingpressure at each pressure sensor forming the pressure sensor array 11(S12). The gripping pressure change amount calculation section 13 aacquires the time-series changes in gripping pressure at each pressuresensor and determines whether the amount of change in gripping pressureper unit time at any pressure sensor exceeds the predetermined value(SS13 a). The change frequency counting section 23 b counts the numberof times the amount of change in gripping pressure per unit time exceedsthe predetermined value (change frequency) in each predetermined periodof time (SS23 b). The screen orientation acquisition section 31 acquiresthe screen orientation (top-to-bottom direction) of the portableterminal 40 (S31). The placement area acquisition section 71 specifiesan optimum placement area for a controllable object in accordance withthe acquired screen orientation (top-to-bottom direction) and a changefrequency exceeding point obtained as a gripping pressure change point(S71). The operation of the placement area acquisition section 71 hasbeen described in detail in “Operation of specifying optimum placementarea in placement area acquisition section 71”. In contrast, when nochange frequency exceeding point exists at any of the pressure sensors,the placement area acquisition section 71 determines that the operationstate is two-handed operation and does not execute the subsequentprocesses (S71). The object placement correcting section 53 corrects theplacement of the controllable object in accordance with the placementarea specified by the placement area acquisition section 71 (S53). Inthe same way as the placement area acquisition section 51, describedbefore, when the placement area acquisition section 71 determines thatthe operation state is two-handed operation and does not execute thesubsequent processes (does not acquire a placement area), the objectplacement correcting section 53 may re-position the controllable objectat a position suited to two-handed operation (default position).

In the portable terminal 40 of this embodiment, the screen orientationacquisition section 31 acquires the screen orientation (top-to-bottomdirection), and the placement area acquisition section 71 acquires anoptimum placement area according to whether the user's operation stateis left-hand gripping and left-handed operation, right-hand gripping andright-handed operation, or two-handed operation by using two pieces ofinformation (top-to-bottom direction and the position of changefrequency exceeding point). Accordingly, besides the advantages of thesecond embodiment, a further-limited optimum placement area can beacquired.

FIFTH EMBODIMENT

The portable terminal 50 according to the fifth embodiment, obtained bytaking into consideration variability in controlling finger movementrange among individual users, by acquiring an optimum placement areawith the use of touch sensitive screen operation history (operationlog), in the portable terminal 10 in the first embodiment, will bedescribed next in detail with reference to FIGS. 20 and 21. FIG. 20 is ablock diagram showing the configuration of the portable terminal 50 inthis embodiment. FIG. 21 is a flowchart illustrating the operation ofthe portable terminal 50 in this embodiment. The portable terminal 50 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 13,the placement area acquisition section 61, the touch-sensitive-screenlogger 82, and the object placement correcting section 53. The grippingpressure change point detection unit 13 includes the gripping pressurechange amount calculation section 13 a. This embodiment differs from thefirst embodiment in that the placement area storage 52 in the firstembodiment is replaced with the touch-sensitive-screen logger 82 in thepresent embodiment, and the placement area acquisition section 51 in thefirst embodiment is replaced with the placement area acquisition section61 in the present embodiment. A description of components denoted by thesame reference numerals as in the first embodiment will be omitted inthis embodiment.

As described in “Operation principle of placement area acquisitionsection 61”, the touch-sensitive-screen logger 82 records an operationlog for each gripping pressure change point separately only when agripping pressure change point appears at any of the edges of theportable terminal 50. A controllable range is obtained for eachoperation log acquired for each gripping pressure change point. Morespecifically, a circular area having a predetermined radius needs to beacquired from a touch sensitive screen pressing position for theacquisition of one piece of operation log. The touch-sensitive-screenlogger 82 can acquire, for example, as a controllable range, an areathat includes all circular areas obtained by acquiring a predeterminednumber of pieces of operation log. The placement area acquisitionsection 61 manipulates the obtained controllable range (for example,converts the controllable range into a simple-shape area), or specifiesthe obtained controllable range as an optimum placement area (S61). Incontrast, when no change point exists at any of the pressure sensors,the placement area acquisition section 61 determines that the operationstate is two-handed operation and does not execute the subsequentprocesses (S61). The object placement correcting section 53 corrects theplacement of the controllable object in accordance with the placementarea specified by the placement area acquisition section 61 (S53). Inthe same way as the placement area acquisition section 51, describedbefore, when the placement area acquisition section 61 determines thatthe operation state is two-handed operation and does not execute thesubsequent processes (does not acquire a placement area), the objectplacement correcting section 53 may re-position the controllable objectat a position suited to two-handed operation (default position).

As described before, since the portable terminal 50 in the presentembodiment does not have a screen orientation acquisition section 31,the screen orientation (top-to-bottom direction) is unknown. Therefore,the controllable range calculated for each gripping pressure changepoint may include both an operation log with the right thumb and anoperation log with the left thumb. When this range is specified as anoptimum placement area, the optimum placement area includes a small butunnecessary area, as described with reference to FIG. 7. However, sincethe placement area acquisition section 61 approximately acquires anoptimum placement area according to the touch-sensitive-screen operationhistory (operation log) while variability in controlling finger movementrange among individual users is taken into account, user convenience isfurther improved.

SIXTH EMBODIMENT

The portable terminal 60 according to the sixth embodiment, obtained bytaking into consideration variability in controlling finger movementrange among individual users, by acquiring an optimum placement areawith the use of touch sensitive screen operation history (operationlog), in the portable terminal 20 in the second embodiment, will bedescribed next in detail with reference to FIGS. 22 and 23. FIG. 22 is ablock diagram showing the configuration of the portable terminal 60 inthis embodiment. FIG. 23 is a flowchart illustrating the operation ofthe portable terminal 60 in this embodiment. The portable terminal 60 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 23,the placement area acquisition section 61, the touch-sensitive-screenlogger 82, and the object placement correcting section 53. The grippingpressure change point detection unit 23 includes the gripping pressurechange amount calculation section 13 a and the change frequency countingsection 23 b. This embodiment differs from the second embodiment in thatthe placement area storage 52 in the second embodiment is replaced withthe touch-sensitive-screen logger 82 in the present embodiment, and theplacement area acquisition section 51 in the second embodiment isreplaced with the placement area acquisition section 61 in the presentembodiment. A description of components denoted by the same referencenumerals as in the second embodiment will be omitted in this embodiment.

As described in “Operation principle of placement area acquisitionsection 61”, the touch-sensitive-screen logger 82 records an operationlog for each gripping pressure change point separately only when agripping pressure change point appears at any of the edges of theportable terminal 60. A controllable range is obtained for eachoperation log acquired for each gripping pressure change point. Morespecifically, a circular area having a predetermined radius needs to beacquired from a touch sensitive screen pressing position for theacquisition of one piece of operation log. The touch-sensitive-screenlogger 82 can acquire, for example, as a controllable range, an areathat includes all circular areas obtained by acquiring a predeterminednumber of pieces of operation log. The placement area acquisitionsection 61 manipulates the obtained controllable range (for example,converts the controllable range into a simple-shape area), or specifiesthe obtained controllable range as an optimum placement area (S61). Incontrast, when no change frequency exceeding point exists at any of thepressure sensors, the placement area acquisition section 61 determinesthat the operation state is two-handed operation and does not executethe subsequent processes (S61). The object placement correcting section53 corrects the placement of the controllable object in accordance withthe placement area specified by the placement area acquisition section61 (S53). In the same way as the placement area acquisition section 51,described before, when the placement area acquisition section 61determines that the operation state is two-handed operation and does notexecute the subsequent processes (does not specify a placement area),the object placement correcting section 53 may re-position thecontrollable object at a position suited to two-handed operation(default position).

As described before, since the portable terminal 60 in the presentembodiment does not have a screen orientation acquisition section 31,the screen orientation (top-to-bottom direction) is unknown. Therefore,the controllable range calculated for each gripping pressure changepoint may include both an operation log with the right thumb and anoperation log with the left thumb. When this range is specified as anoptimum placement area, the optimum placement area includes a small butunnecessary area, as described with reference to FIG. 7. However, sincethe placement area acquisition section 61 approximately acquires anoptimum placement area according to the touch-sensitive-screen operationhistory (operation log) while variability in controlling finger movementrange among individual users is taken into account, user convenience isfurther improved.

SEVENTH EMBODIMENT

The portable terminal 70 according to the seventh embodiment, obtainedby taking into consideration variability in controlling finger movementrange among individual users, by acquiring an optimum placement areawith the use of touch sensitive screen operation history (operationlog), in the portable terminal 30 in the third embodiment, will bedescribed next in detail with reference to FIGS. 24 and 25. FIG. 24 is ablock diagram showing the configuration of the portable terminal 70 inthis embodiment. FIG. 25 is a flowchart illustrating the operation ofthe portable terminal 70 in this embodiment. The portable terminal 70 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 13,the screen orientation acquisition section 31, the placement areaacquisition section 81, the touch-sensitive-screen logger 82, and theobject placement correcting section 53. The gripping pressure changepoint detection unit 13 includes the gripping pressure change amountcalculation section 13 a. This embodiment differs from the thirdembodiment in that the placement area storage 52 in the third embodimentis replaced with the touch-sensitive-screen logger 82 in the presentembodiment, and the placement area acquisition section 71 in the thirdembodiment is replaced with the placement area acquisition section 81 inthe present embodiment. A description of components denoted by the samereference numerals as in the third embodiment will be omitted in thisembodiment.

As described in “Operation principle of placement area acquisitionsection 81”, the touch-sensitive-screen logger 82 records a touchsensitive screen operation log for each combination of the operationstate and the screen orientation in a time zone during which thecombination of the operation state and the screen orientation remainsunchanged. More specifically, for example, an operation log is recordedwhen the operation state is left-hand gripping and left-handed operationand when the top of the screen is displayed at the top of the figure. Inaddition, an operation log is separately recorded when the operationstate is left-hand gripping and left-handed operation and when the topof the screen is displayed at the bottom of the figure. In addition, anoperation log is separately recorded when the operation state isright-hand gripping and right-handed operation and when the top of thescreen is displayed at the top of the figure. These operation logs arerecorded separately for the corresponding combinations of the operationstates and the screen orientation, and a controllable range is obtainedfor each operation log acquired for each combination of the operationstate and the screen orientation.

As described in “Operation principle of placement area acquisitionsection 61”, an operation log may be acquired for each classified casefor each gripping pressure change point. In the present embodiment,however, it is not necessarily to classify the operation log into casesfor each gripping pressure change point. When the combination of theoperation state and the screen orientation is identified, since the usergrips the terminal according to his or her gripping habit to someextent, the position where a gripping pressure change point appears isfixed and it is not expected that the gripping pressure change pointchanges significantly. Therefore, the touch-sensitive-screen logger 82acquires an operation log for each combination of the operation stateand the screen orientation. More specifically, a circular area having apredetermined radius needs to be acquired from a touch sensitive screenpressing position for the acquisition of one piece of operation log. Thetouch-sensitive-screen logger 82 can acquire, for example, as acontrollable range, an area that includes all circular areas obtained byacquiring a predetermined number of pieces of operation log. Theplacement area acquisition section 81 manipulates the obtainedcontrollable range (for example, converts the controllable range into asimple-shape area), or specifies the obtained controllable range as anoptimum placement area (S81). In contrast, when no change point existsat any of the pressure sensors, the placement area acquisition section81 determines that the operation state is two-handed operation and doesnot execute the subsequent processes (S81). The object placementcorrecting section 53 corrects the placement of the controllable objectin accordance with the placement area specified by the placement areaacquisition section 81 (S53). In the same way as the placement areaacquisition section 51, described before, when the placement areaacquisition section 81 determines that the operation state is two-handedoperation and does not execute the subsequent processes (does notspecify a placement area), the object placement correcting section 53may re-position the controllable object at a position suited totwo-handed operation (default position).

As described above, according to the portable terminal 70 of thisembodiment, the screen orientation acquisition section 31 acquires thescreen orientation (top-to-bottom direction), and the placement areaacquisition section 81 acquires an optimum placement area according tothe touch sensitive screen operation history (operation log). Therefore,besides the advantages of the third embodiment, an optimum placementarea can be specified while the variability in controlling fingermovement range among individual users is taken into consideration,further improving user convenience.

EIGHTH EMBODIMENT

The portable terminal 80 according to the eighth embodiment, obtained bytaking into consideration variability in controlling finger movementrange among individual users, by acquiring an optimum placement areawith the use of touch sensitive screen operation history (operationlog), in the portable terminal 40 in the fourth embodiment, will bedescribed next in detail with reference to FIGS. 26 and 27. FIG. 26 is ablock diagram showing the configuration of the portable terminal 80 inthis embodiment. FIG. 27 is a flowchart illustrating the operation ofthe portable terminal 80 in this embodiment. The portable terminal 80 inthis embodiment includes the pressure sensor array 11, the grippingpressure logger 12, a gripping pressure change point detection unit 23,the screen orientation acquisition section 31, the placement areaacquisition section 81, the touch-sensitive-screen logger 82, and theobject placement correcting section 53. The gripping pressure changepoint detection unit 23 includes the gripping pressure change amountcalculation section 13 a and the change frequency counting section 23 b.This embodiment differs from the fourth embodiment in that the placementarea storage 52 in the fourth embodiment is replaced with thetouch-sensitive-screen logger 82 in the present embodiment, and theplacement area acquisition section 71 in the fourth embodiment isreplaced with the placement area acquisition section 81 in the presentembodiment. A description of components denoted by the same referencenumerals as in the fourth embodiment will be omitted in this embodiment.

As described in “Operation principle of placement area acquisitionsection 81”, the touch-sensitive-screen logger 82 records a touchsensitive screen operation log for each combination of the operationstate and the screen orientation in a time zone during which thecombination of the operation state and the screen orientation remainsunchanged. More specifically, for example, an operation log is recordedwhen the operation state is left-hand gripping and left-handed operationand when the top of the screen is displayed at the top of the figure. Inaddition, an operation log is separately recorded when the operationstate is left-hand gripping and left-handed operation and when the topof the screen is displayed at the bottom of the figure. In addition, anoperation log is separately recorded when the operation state isright-hand gripping and right-handed operation and when the top of thescreen is displayed at the top of the figure. These operation logs arerecorded separately for the corresponding combinations of the operationstates and the screen orientation, and a controllable range is obtainedfor each operation log acquired for each combination of the operationstate and the screen orientation.

As described in “Operation principle of placement area acquisitionsection 61”, an operation log may be acquired for each classified casefor each gripping pressure change point. In the present embodiment,however, it is not necessarily to classify the operation log into casesfor each gripping pressure change point. When the combination of theoperation state and the screen orientation is identified, since the usergrips the terminal according to his or her gripping habit to someextent, the position where a gripping pressure change point appears isfixed and it is not expected that the gripping pressure change pointchanges significantly. Therefore, the touch-sensitive-screen logger 82acquires an operation log for each combination of the operation stateand the screen orientation. More specifically, a circular area having apredetermined radius needs to be acquired from a touch sensitive screenpressing position for the acquisition of one piece of operation log. Thetouch-sensitive-screen logger 82 can acquire, for example, as acontrollable range, an area that includes all circular areas obtained byacquiring a predetermined number of pieces of operation log. Theplacement area acquisition section 81 manipulates the obtainedcontrollable range (for example, converts the controllable range into asimple-shape area), or specifies the obtained controllable range as anoptimum placement area (S81). In contrast, when no change frequencyexceeding point exists at any of the pressure sensors, the placementarea acquisition section 81 determines that the operation state istwo-handed operation and does not execute the subsequent processes(S81). The object placement correcting section 53 corrects the placementof the controllable object in accordance with the placement areaspecified by the placement area acquisition section 81 (S53). In thesame way as the placement area acquisition section 51, described before,when the placement area acquisition section 81 determines that theoperation state is two-handed operation and does not execute thesubsequent processes (does not specify or acquire a placement area), theobject placement correcting section 53 may re-position the controllableobject at a position suited to two-handed operation (default position).

As described above, according to the portable terminal 80 of thisembodiment, the screen orientation acquisition section 31 acquires thescreen orientation (top-to-bottom direction), and the placement areaacquisition section 81 acquires an optimum placement area according tothe touch sensitive screen operation history (operation log). Therefore,besides the advantages of the fourth embodiment, an optimum placementarea can be specified while the variability in controlling fingermovement range among individual users is taken into consideration,further improving user convenience.

Each type of processing described above may be executed not onlytime-sequentially according to the order in the description but also inparallel or individually when necessary or according to the processingcapability of each apparatus that executes the processing. Appropriatechanges can be made to the above embodiments without departing from thescope of the present invention.

When the configurations described above are implemented by a computer,the processing details of the functions that should be provided by eachapparatus are described in a program. When the program is executed bythe computer, the processing functions are implemented on the computer.

The program containing the processing details can be recorded in acomputer-readable recording medium. The computer-readable recordingmedium can be any type of medium, such as a magnetic recording device,an optical disc, a magneto-optical recording medium, or a semiconductormemory.

The program is distributed by selling, transferring, or lending aportable recording medium, such as a DVD or a CD-ROM, with the programrecorded on it, for example. The program may also be distributed bystoring the program in a storage unit of a server computer andtransferring the program from the server computer to another computerthrough a network.

A computer that executes this type of program first stores the programrecorded on a portable recording medium or the program transferred fromthe server computer in its storage unit. Then, the computer reads theprogram stored in its storage unit and executes processing in accordancewith the read program. In a different program execution form, thecomputer may read the program directly from the portable recordingmedium and execute processing in accordance with the program, or thecomputer may execute processing in accordance with the program each timethe computer receives the program transferred from the server computer.Alternatively, the above-described processing may be executed by aso-called application service provider (ASP) service, in which theprocessing functions are implemented just by giving program executioninstructions and obtaining the results without transferring the programfrom the server computer to the computer. The program of this formincludes information that is provided for use in processing by thecomputer and is treated equivalent to a program (something that is not adirect instruction to the computer but is data or the like that hascharacteristics that determine the processing executed by the computer).

In the description given above, each apparatus is implemented byexecuting the predetermined program on the computer, but at least a partof the processing details may be implemented by hardware.

1. A mobile information terminal provided with a pressure sensor arraythat acquires a gripping pressure distribution, the mobile informationterminal comprising: a gripping pressure logger adapted to recordtime-series changes in gripping pressure at each pressure sensor formingthe pressure sensor array; a gripping pressure change point detectionunit comprising a gripping pressure change amount calculation sectionadapted to acquire time-series changes in gripping pressure at eachpressure sensor and to determine whether the amount of change ingripping pressure per unit time exceeds a predetermined value at anypressure sensor; and a placement area acquisition section adapted toacquire a placement area for a controllable object with reference to aposition where the amount of change in gripping pressure per unit timeexceeds the predetermined value, the position being hereafter referredto as a change point, when the amount of change in gripping pressure perunit time exceeds the predetermined value at any pressure sensor.
 2. Themobile information terminal according to claim 1, wherein the grippingpressure change point detection unit further comprises a changefrequency counting section adapted to count the number of times theamount of change in gripping pressure per unit time exceeds thepredetermined value in each predetermined period of time, the numberbeing hereafter referred to as a change frequency; and the placementarea acquisition section acquires the placement area for thecontrollable object with reference to a position where the countedchange frequency exceeds a predetermined value, the position beinghereafter referred to as a change frequency exceeding point, in a periodof time in which the counted change frequency exceeds the predeterminedvalue.
 3. The mobile information terminal according to claim 1, furthercomprising a screen orientation acquisition section adapted to acquirethe screen orientation of the mobile information terminal, wherein theplacement area acquisition section acquires the placement area for thecontrollable object in accordance with the acquired screen orientationand the change point.
 4. The mobile information terminal according toclaim 2, further comprising a screen orientation acquisition sectionadapted to acquire the screen orientation of the mobile informationterminal, wherein the placement area acquisition section acquires theplacement area for the controllable object in accordance with theacquired screen orientation and the change frequency exceeding point. 5.The mobile information terminal according to claim 3, wherein, when thechange point is on the right edge of the mobile information terminalwith reference to the screen orientation, the placement area acquisitionsection determines that the operation state of the mobile informationterminal is right-hand gripping and right-handed operation; when thechange point is on the left edge of the mobile information terminal withreference to the screen orientation, the placement area acquisitionsection determines that the operation state of the mobile informationterminal is left-hand gripping and left-handed operation; and theplacement area acquisition section acquires the placement area for thecontrollable object in accordance with the change point.
 6. The mobileinformation terminal according to claim 4, wherein, when the changefrequency exceeding point is on the right edge of the mobile informationterminal with reference to the screen orientation, the placement areaacquisition section determines that the operation state of the mobileinformation terminal in the period of time is right-hand gripping andright-handed operation; when the change frequency exceeding point is onthe left edge of the mobile information terminal with reference to thescreen orientation, the placement area acquisition section determinesthat the operation state of the mobile information terminal in theperiod of time is left-hand gripping and left-handed operation; and theplacement area acquisition section acquires the placement area for thecontrollable object in each period of time in accordance with the changefrequency exceeding point.
 7. A placement area acquisition methodexecuted by a mobile information terminal provided with a pressuresensor array that acquires a gripping pressure distribution, theplacement area acquisition method comprising: a gripping pressurelogging step of recording time-series changes in gripping pressure ateach pressure sensor forming the pressure sensor array; a grippingpressure change point detection step comprising a gripping pressurechange amount calculation sub step of acquiring time-series changes ingripping pressure at each pressure sensor and of determining whether theamount of change in gripping pressure per unit time exceeds apredetermined value at any pressure sensor; and a placement areaacquisition step of acquiring, when the amount of change in grippingpressure per unit time exceeds the predetermined value at any pressuresensor, a placement area for a controllable object with reference to aposition where the amount of change in gripping pressure per unit timeexceeds the predetermined value, the position being hereafter referredto as a change point.
 8. The placement area acquisition method accordingto claim 7, wherein the gripping pressure change point detection stepfurther comprises a change frequency counting sub step of counting thenumber of times the amount of change in gripping pressure per unit timeexceeds the predetermined value in each predetermined period of time,the number being hereafter referred to as a change frequency; and in theplacement area acquisition step, in a period of time in which thecounted change frequency exceeds a predetermined value, the placementarea for the controllable object is acquired with reference to aposition where the counted change frequency exceeds a predeterminedvalue.
 9. The placement area acquisition method according to claim 7,further comprising a screen orientation acquisition step of acquiringthe screen orientation of the mobile information terminal; wherein, inthe placement area acquisition step, the placement area for thecontrollable object is acquired in accordance with the acquired screenorientation and the change point.
 10. A non-transitory computer readablerecording medium on which is recorded a program for causing a computerto execute the placement area acquisition method according to claim 7.11. A non-transitory computer readable recording medium on which isrecorded a program for causing a computer to execute the placement areaacquisition method according to claim
 8. 12. A non-transitory computerreadable recording medium on which is recorded a program for causing acomputer to execute the placement area acquisition method according toclaim 9.